酶活性部位的表皮相互作用网络通过大规模的深度突变扫描揭示了
Allison Judge1, Banumathi Sankaran2, Liya Hu1
1Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX 77030.
概括
在CTX-Mβ-lactamase中研究了表观性或上下文依赖的氨基酸相互作用. 突变增强功能的积极表达是常见的,由基质相互作用介导,告知酶工程.
科学领域:
- 生物化学 生化学
- 分子生物学分子生物学
- 酶动力学 酶动力学
背景情况:
- 合作性氨基酸相互作用对于蛋白质功能至关重要.
- 一种突变影响另一种突变影响的基因相互作用 - - 表观症 (epistasis) 反映了这些合作性.
- CTX-Mβ-乳酸酶是一种赋予抗生素耐药性的酶,可以作为研究酶活性位点表皮病的模型.
研究的目的:
- 为了研究CTX-Mβ-lactamase的活性部位内的表皮病.
- 了解一个位置的氨基酸替代如何影响另一个位置的要求.
- 阐明驱动表观症的生物化学机制,并为酶工程提供信息.
主要方法:
- 在CTX-Mβ-lactamase中的17个活性位点位置生成了所有双向突变.
- 使用下一代测序对两种β-乳酸抗生素进行量化酶功能.
- 将双重突变的功能与预测的单一突变的附加效应进行比较,以确定表现症.
主要成果:
- 确定了氨基酸替代之间的正 (协同作用) 和负 (对抗作用) 间的表现.
- 证明积极的表皮病在整个活性部位中普遍存在,并通过基质相互作用进行介导.
- 表明耐受替代的残留物作为补偿元素,驱动积极的表现,并确定了催化改变的双重突变 (E166Y/N170G).
结论:
- 表观性是酶活性部位功能的重要因素,由基质相互作用和补偿突变驱动.
- 了解这些上下文依赖的氨基酸相互作用是预测蛋白质功能的关键.
- 这些发现为合理的酶工程和抗生素耐药机制提供了洞察力.
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